Insulating Concrete Form Systems ("ICFS") are known which act as a form to contain the fluid concrete while it solidifies, and also provide insulation for the finished structure. ICFS utilise a plurality of individual units or blocks, assembled in an interlocking arrangement, to create the forms for the concrete walls Each block comprises a pair of foamed plastic panels, which are held together with a plurality of ties.
The ties are truss-like and comprise flange portions which reside within the foam panels and an intermediate web portion connecting the flange portions, thus securing and holding the panel portions. One such example is disclosed in U.S. Pat. No. 4,229,920 to Lount, issued Oct. 28, 1980 who teaches use of a block having a multi-component tie.
More contemporary ICFS designs have implemented ties having integral flanges and web portions. Examples of this construction include U.S. Pat. No. 5,390,459 to Mensen, U.S. Pat. No. 4,884,382 to Horobin and U.S. Pat. No. 4,731,968 to Obino.
Horobin teaches slide-in ties which have complementary flanges and "T" slots formed in the panels. Each slot extends from the top of the panel to a point just lower than the mid-point. Accordingly, both the tie and the flange portions of the tie are substantially less in height than the panel. The flange itself has an "H" profile in plan; the outer portion for engaging the panel's "T"-slot, and the inner portion for stabilizing the inner face of the panel. The tie's web comprises three horizontal tension members, joined together at the flanges.
Obino provides a tie similar to Horobin, but the flanges are moulded into the foam of the panel. Both the web and flanges are substantially shorter than the panels. The web structure is continuous; lacking any holes.
In Mensen, the tie is moulded into the panel with the flange located flush with the outside of the panel. The flange extends substantially the full height of the panel. In side view, the tie resembles an "H", the horizontal dash representing the web portion being much narrower that the flanges. Diagonal gussets extend from the web's midpoint to points adjacent the distal ends of each flange.
These above designs result in non-optimal distribution of the hydrostatic stress of the fluid concrete across the narrow central web portion of the tie and in the upper and lower portions of the foam panels. In Horobin and Obino, the foam portion is completely unsupported by the tie at the panel's upper and lower ends. In Mensen, the tips of the flanges are inadequately supported by the gussets. The result is excessive deformation of the top and bottom portions of the foam panels when filled with concrete. This is especially apparent when high vertical concrete lifts (a full; 8' high wall) are poured in a single stage.
Mensen, Horobin and Obino permit attachment of interior and exterior surface finishing materials such as drywall or siding to the vertically-oriented flange portions of the ties. Of these three designs, only Mensen provides a flange which extends substantially the full height of the panels and is visible from outside the block for ease of attaching fastening devices.
Conventional systems permit vertical misalignment such that the flanges of adjacent blocks are not always aligned vertically. This poses difficulties for installers who need to accurately locate the flanges when attaching finishing materials
Within the typical dimensions of building construction there is frequently the need for a half-height concrete form block to be used, for example, below and above window openings. Although some ICFS designs provide a custom block having a less-than-standard height, none of the existing designs permits a block to cut horizontally in half to create a "half-height" block which continues to provide independently structurally sound characteristics.
In summary, the blocks of conventional systems, as described above, have the following features in common:
a pair of substantially rectangular foamed plastic panels; PA1 two or more ties which extend across the space between panels for securing the panels in opposing, parallel, and spaced orientation, the spacing forming a cavity therebetween for containing the fluid concrete while it solidifies; PA1 the web portions of the ties being substantially less in height than the panels; and PA1 means associated with the edges of the panels for engaging cooperating means on adjacent blocks in order to assemble the complete wall form system. PA1 inadequate support of hydrostatic pressures; PA1 deficient flange configuration, being either, PA1 that they are too short to provide a convenient support upon which to mechanically fasten finishing materials as in Horobin and Obino, or PA1 that they cause interruption of the integrity of the outer face of the panel, compromising adhesion of surface mount materials like stucco, as is the case in Mensen; and PA1 permitting misalignment of flanges between vertically adjacent blocks, further complicating the mechanical fastening of the finishing materials. PA1 a pair of rectangular foam plastic panels having inner and outer faces, top and bottom and end edges; PA1 at least two ties spaced longitudinally and parallel from each other, each of which extend perpendicularly between the inner faces of the panels so as to space the panels in opposing and parallel orientation, each tie having two opposed flange portions and a web portion extending therebetween, each flange portion forming a vertical stud which extends substantially the height of the panels and is moulded within each panel, the web portion comprising a plurality of horizontally extending members distributed substantially along the full height of the flanges, the web having a majority of its cross-sectional area comprising open space; and PA1 interlocking means along the edges of the panels so that the block interlocks with other blocks when placed adjacent one another.
Disadvantages associated with the above systems include:
Despite attempts to solve various shortcomings of the conventional blocks, the applicant is not aware of a system which provides sufficient strength to competently support the hydrostatic head of a full-height wall of fresh concrete, and enables convenient attaching of finishing materials.